This invention relates to a mandrel for winding together a plurality of flexible strip members into a coil or jelly-roll configuration, and to a method of winding using such mandrel.
In the production of coiled capacitors or spirally wound electrochemical cell packs consisting of opposite polarity plates and interposed separator or dielectric, various winding methods and mandrels have been employed. One method uses a driven mandrel (e.g., U.S. Pat. No. 3,298,871 to Binder et al), another employs a driven mandrel and idling pressure rolls (e.g., U.S. Pat. No. 3,839,088 to Hug et al). In still another method of winding, belts are employed together with a free turning solid mandrel, exemplified by U.S. Pat. No. 4,064,725 to Hug et al. The subject invention applies to the driven mandrel type, which may also advantageously employ sizing rolls with or without connecting belts to ensure winding of the element into the desired coiled form, such as an approximate archimedes spiral.